The present invention relates to a tamperproof lid for a container. More particularly, the present invention relates to a tamperproof lid in which a lower ring portion must be substantially completely removed from its connection to the remainder of the lid and also from contact with the upper lip of the container in order to open the container, thus providing a means of protecting against tampering with the contents of the container.
Previous containers having tamperproof lid constructions are described, for example, in the following U.S. Pat. Nos. 3,974,932 to Faulstich; 4,341,318 to Smalley; 4,305,517 to Dennis; 4,281,774 to Mumford; 4,111,329 to Lampman; and 4,103,803 to Irvine. Other closure mechanisms in which a tear strip is provided for removing the cover therefrom are described, for example, in the following U.S. Pat. Nos.: 3,172,557 to Koenig; 3,347,407 to Coolidge; 3,356,250 to Russell; 3,416,697 to Ledzion; and 3,425,592 to Vogel.
By the present invention, there is provided an improved tamperproof lid for a container, wherein a series of toothed or segmented sections are provided around the lower portion of the lid outer periphery which grips the lip or rim of the container. This toothed portion of the lid forms a portion of the tear strip which must be removed in order to remove the lid.
The teeth of the segmented sections of the lid are formed so that, upon an attempt being made to raise the lid, the teeth will engage the lower surface of the rim around the upper periphery of the container in a tight, firm construction which tends to hold more tightly to the rim of the container as any attempt is made to remove the lid. Thus the lid of the present invention may not be removed without destroying the seal provided around the lip or rim of the container. Whereas with other constructions a squeeze type effect is produced, in the present invention there is a finger-like pulling effect so that the harder one pulls, the more tightly the lid construction will hold to the rim of the container.
The tamperproof lid of the present invention thus provides a positive lock which does not depend upon friction or the resilience of the lid or cap. In one embodiment, the lid may be constructed of polyethylene in a thickness of from about 0.008 to 0.015 inches in thickness.
Accordingly, it is a primary object of the present invention to provide a lid for a container in which the lid will give evidence of tampering or an attempt to open the lid.
It is another object of the invention to provide a positive lock-type lid for a container which will adhere closely and tightly to the rim of the container.
It is a further object of the invention to provide a tamperproof lid which may be easily employed with present capping equipment resulting in a simple and effective means of closure for a container.
It is another object of the invention to provide a lid member having a series of toothed segments or portions which assist in maintaining closure of the container while also providing a means of tension to prevent lid removal in the event of tampering.